In connection with communication between electrical units, for example when electrical members of various types communicate with an electronic unit for conveying information to or collecting information from these members, demands for signal adaptation between the electrical units will immediately arise. To carry out this signal adaptation, an input or output unit can be connected nearest the electrical member, which input or output unit is intended to see to the need of signals of the connected member or the electronic unit with respect to current and voltage level as well as signal type. Both analog and digital signal types occur. In this description only digital signal types are described.
In modularized electronic building systems, special input and output units, I/O units, occur, in this case digital I/O units, DI/DO, which take care of the above-mentioned signal adaptation. Such building systems are utilized, for example, within car electronics and industrial process adaptation systems. To cover as many of the signal types occurring as possible, the DI/DO units are designed with a plurality of different functions for adaptation to various demands. The relevant functions of a DI/DO unit are primarily its use as DI unit or DO unit as well as cable supervision, current level warning, current level limitation, temperature level warning, overtemperature protection and the possibility of selection of the voltage range.
All of the above functions are each currently realized in known technique within the field. To be able to satisfy different requirements for fields of applications for DI/DO units, such units have been designed in a number of different variants corresponding to different specifications of requirements. This causes problems in the design and installation of electronics systems according to the above, since each individual DI/DO unit must be specified. A requirement for realization of one single DI/DO unit will naturally arise, which, per se, comprises all of the above desirable functions.
Modularized DI/DO units already exist on the market, which units integrate several of the above-mentioned functions in one and the same module, however, not all of those enumerated above at the same time. In the following description, a DI/DO module will be described which claims to possess all of the above-mentioned functions available and integrated in one and the same module.